US4249837A - Method of and apparatus for supporting an overburden - Google Patents

Method of and apparatus for supporting an overburden Download PDF

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Publication number
US4249837A
US4249837A US05/957,355 US95735578A US4249837A US 4249837 A US4249837 A US 4249837A US 95735578 A US95735578 A US 95735578A US 4249837 A US4249837 A US 4249837A
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Prior art keywords
prop
roof
casing
arrangement
prop casing
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US05/957,355
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English (en)
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Klaus Spies
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HEINTZMAN GmbH AND Co
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HEINTZMAN GmbH AND Co
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Priority to US05/957,355 priority Critical patent/US4249837A/en
Priority to AU46307/79A priority patent/AU4630779A/en
Priority to DE19792941663 priority patent/DE2941663A1/de
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    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D15/00—Props; Chocks, e.g. made of flexible containers filled with backfilling material
    • E21D15/005—Props; Chocks, e.g. made of flexible containers filled with backfilling material characterised by the material
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D15/00—Props; Chocks, e.g. made of flexible containers filled with backfilling material
    • E21D15/14—Telescopic props
    • E21D15/16—Telescopic props with parts held together by positive means, with or without relative sliding movement when the prop is subject to excessive pressure
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D15/00—Props; Chocks, e.g. made of flexible containers filled with backfilling material
    • E21D15/14—Telescopic props
    • E21D15/28—Telescopic props with parts held relatively to each other by friction or gripping

Definitions

  • the present invention is directed to a method of supporting an overburden, for example the roof of an underground excavation.
  • the invention is also directed to apparatus for carrying out the method.
  • a more particular object is to provide an improved method of supporting an overburden, especially the roof of an underground excavation.
  • Another object is to provide such a method which facilitates the erection and removal of roof supports and which reduces the attendant costs.
  • a further object is to provide an improved system or arrangement for supporting an overburden, particularly a roof of an underground excavation such as a mine.
  • a concomitant object is the provision of such a system which is simpler than those known from the prior art, is much less expensive and is much ligher in weight and therefore easier to handle in all types of environments.
  • Still a further object is to provide a system of the kind under discussion which utilizes support elements that are inexpensive and light in weight so that they can be readily moved and installed.
  • Yet another object is to provide special means for protecting the support elements against damage due to overloading.
  • the method may comprise the steps of providing a hollow prop casing composed of at least two telescopable sections, erecting the prop casing and telescoping it apart until it bears upon the floor and upon the roof to be supported, biasing the sections of the prop casing in the telescoped-apart position against the floor and the roof, respectively, and filling the prop casing with a hardenable substance in flowable condition so that the substance, upon hardening thereof, forms a solid column which by itself is able to support the roof.
  • An arrangement (i.e. system) for supporting an overburden may comprise a hollow prop casing composed of at least two telescopable sections which can be telescoped apart subsequent to erection of the prop casing so as to bear upon the roof and a floor beneath the same, the sections having sufficient strength to be self-supporting but not to support the roof, means for biasing the sections in their telescoped-apart condition against the floor and the roof, respectively, and means for filling the prop casing with a hardenable substance in flowable condition so that the substance, upon hardening thereof, forms a solid column which by itself is able to support the roof.
  • the novel prop casing has no roof-supporting function at all. It serves merely as a receptacle (in effect as a casting form) for the hardenable substance while the same is still in flowable form.
  • the actual supporting function is performed by the hardenable substance per se, when the same has hardened and forms a solid supporting column within the casing.
  • This makes it possible to produce the prop casing of very inexpensive materials which are extremely light in weight.
  • synthetic plastic materials such as polyvinylchloride or polyethylene may be used and need only have a thickness which is sufficient to contain the weight of hardenable substance filled into the prop casing, for the period until the substance solidifies.
  • the filler substance itself can also be an inexpensive material. It may be a concrete slurry, i.e. a mixture of water and a quick-binding cement, preferably in form of cement powder. Aggregate is preferably added (it may already be accommodated in the prop casing before the slurry is admitted into the same) to further increase the strength of the column being formed. In lieu of, or in addition to the aggregate, the prop casing may also contain at least some of the cement powder which is ultimately required to make the slurry.
  • gypsum which again is preferably reinforced with aggregate, or a two-component adhesive system of synthetic plastic material which, when the two components are admixed with one another, will harden and form the requisite solid column.
  • aggregate is employed in addition, to become embedded in the two-component system so as to further reinforce the same.
  • the aggregate can be in form of gravel or the like as is known from the construction industry.
  • gypsum gypsum
  • some or all of the gypsum powder required to form the solid column may already be contained in the hollow prop casing before water is admitted into the same, and if a two-component adhesive system is used one of the two components may already be wholly or in part accommodated in the hollow prop casing before the other component is admitted into the same.
  • the aggregate may be admitted from outside during admission of the other component, or of the water, but preferably will already be present in the interior of the prop casing at this time.
  • FIG. 1 is a vertical section through a pit prop casing according to the invention
  • FIG. 2 is a section taken on line II--II of FIG. 1;
  • FIG. 3 is a side view of the telescopable reinforcing structure used in the embodiment of FIG. 1;
  • FIG. 4 is a somewhat diagrammatic side view, showing a device for injecting hardenable substance into a prop casing according to the invention, together with the supply elements which cooperate with the device;
  • FIG. 5 is a perspective view, showing a detail of FIG. 4 on an enlarged scale
  • FIG. 6 is a top perspective of an element for use with the device of FIGS. 4 and 5;
  • FIGS. 7A-7E are respective cross-sections through an installed prop casing according to the invention, showing the casing before, during and after filling with a hardenable substance;
  • FIG. 8 is a somewhat diagrammatic vertical section through a pit prop socket which permits the removal of the installed pit prop even when the same is under load;
  • FIG. 9 is a view analogous to FIG. 8 but illustrating a different embodiment of a pit prop socket
  • FIG. 10 is a vertical section through one embodiment of a pit prop overload protector
  • FIG. 11 is a view analogous to FIG. 10 but showing a different embodiment of the overload protector
  • FIG. 12 is a vertical section through an overload protector which is a modification of the one in FIG. 11;
  • FIG. 13 is a vertical section through an overload protector according to a further embodiment
  • FIG. 14 is a view similar to that in FIG. 13 but showing an overload protector according to still another embodiment
  • FIG. 15 is a fragmentary vertical section through an embodiment of an overload protector which is a modification of the one shown in FIG. 14;
  • FIG. 16 is a fragmentary vertical section showing still another embodiment of the invention.
  • FIGS. 1-3 An exemplary embodiment of a pit prop casing according to the invention is illustrated in FIGS. 1-3.
  • the casing is composed of a light-weight, thin-walled outer tubular section 1 of e.g. cardboard and a similar inner tubular section 2 which is telescopable relative to the section 1.
  • the ends of the sections 1, 2 are closed by end caps 3 and 4, respectively, which may be of a different material (e.g. metal, wood, synthetic plastic) and are suitably secured to the respective sections, as by e.g. adhesive bonding or any other suitable manner.
  • a reinforcing arrangement may be provided in the casing 1, 2 which is analogous to the type of arrangements used in reinforced concrete.
  • Such an arrangement must, of course, also be telescopable to accommodate itself to changes in the length (height) of the prop casing as the sections 1, 2 of the same are telescoped apart or together.
  • the reinforcing arrangement can be in form of steel wire mesh or the like. In the embodiment illustrated in FIGS. 1-3 it is in form of two telescopable "baskets" that are arranged in the sections 1, 2, respectively.
  • the inner basket is composed of an annulus of steel rods or bars 5 which are connected at one end (e.g. by welding) to a ring 6. Their other ends may be connected to a similar ring or, as illustrated, they may be secured to (e.g. embedded in) the end cap 3.
  • the outer basket in section 2 is similarly constructed of an annulus of steel rods or bars 7; the diameter of this annulus is greater than that of the annulus of rods 5 and the free ends of rods 7 are connected to a correspondingly larger ring 8. Their other ends may be secured to (e.g. embedded in) the end cap 4 as shown, or they may be connected to another ring.
  • the basket composed of rods 5 and ring 6 is then telescopically guided in the basket composed of rods 7 and ring 8; of course, this relationship may be reversed.
  • the ring 8 is advantageously secured at the free end of the section 2, e.g. adhesively or by having portions projecting into recesses of the wall of section 2 or in any other suitable manner.
  • Section 2 is exteriorly surrounded by a helical expansion spring 8 (a different type of spring could also be used). Section 2 is provided, preferably in the end cap 4, with a vent hole 9 to permit the escape of air from the interior of the prop casing as hardenable substance is admitted into the same.
  • a helical expansion spring 8 a different type of spring could also be used.
  • the prop casing When the prop casing is to be used, it is placed in upright position and the section 2 is telescoped out of the section 1 until its end cap 4 bears upon the roof to be supported whereas the end cap 3 bears upon the floor (of course, contact with the floor and/or roof may be direct or some other element may be interposed, as dictated by the requirements of a particular situation).
  • the spring 8 is now compressed towards the upper edge face 1a of the section 1, on which it rests.
  • FIGS. 1-3 show a still simpler possibility, namely, the retainers 10 may be in form of pointed spikes or the like which are simply hammered into the wall of section 2.
  • the hardenable substance in flowable state (e.g. one of the earlier mentioned substances) is admitted into the prop casing via a port 11 until the interior of the prop casing is completely filled with the substance.
  • aggregate and/or some or all of one of the two components making up the hardenable substance e.g.
  • cement powder and water; water and gypsum powder; two-component synthetic plastic material may already be present in the interior of the casing before filling is commenced via the port 11, or may be admitted through this port before the other component or components are admitted.
  • vent 9 assures that air can escape from the casing during the filling operation, so as not to interfere with the hardening of the substance and its formation of a solid column of proper density.
  • the material and construction of the prop casing must be such that the hardenable substance can, if necessary, be admitted under a certain amount of pressure to assure proper filling of the casing.
  • the admission of the substance through the port 11 is effected by means of an injecting device D which is shown in FIGS. 4 and 5.
  • This injecting device may (but need not be) pistol or gun shaped and have a trigger 22 which, when depressed, permits flow of substance to the outlet opening 20a of the device D (FIG. 5) which in use is placed against the port 11.
  • the barrel 20 of the device D is preferably provided with a pair of arms 21 that can pivot apart to the position in FIG. 5 when the device is not in use, but which will pivot to the position illustrated in FIG. 7 in which they embrace the section 2. This will be discussed in more detail later on, in connection with FIG. 7.
  • the port 11 may be provided with a one-way valve (not shown) to permit inflow of the pressurized hardenable substance but to prevent the same from flowing out again through the port 11.
  • the device D is provided with connections to which a pair of conduits 23 and 24 is secured.
  • the conduit 23 may have a pump P interposed in it which in turn draws e.g. pulverulent cement of the quick-bonding type (known from the construction industry and therefore requiring no detailed discussion) from the diagrammatically illustrated cement supply.
  • the pump P may of course also be supplied with other materials, for example additives which aid in the rapid bonding of the cement, or such additives may be mixed in with the cement powder.
  • the cement powder could be mixed with aggregate, in which case the pump would have to be capable of transporting such aggregate in addition to the cement powder, or a separate pump for the aggregate would have to be provided to supply it to the device D.
  • the aggregate may also be placed into the prop casing 1, 2 as or before the same is erected, i.e. placed in upright position to bear against the roof to be supported.
  • the conduit 24 communicates with the diagrammatically illustrated water supply, and a pair of valves 25, 25 are interposed in the respective conduit 23, 24 to permit regulation of the flow of the respective substances into the injecting device D.
  • the mixing of the substances may take place in the device D itself so that a slurry composed of the mixed substances issues from the outlet 20a of the device D and enters the port 11.
  • a two-component synthetic adhesive system is used, then one of the components should be supplied via the conduit 23 and the other component via the conduit 24.
  • conduits or containers for the transport of the cement and water (or other components) to the working site. These are considered to be diagrammatically included in the illustration of the conduits 23, 24 and the cement and water supplies as shown.
  • the mixing of the components can take place within the respective prop casing 1, 2, rather than in the device D, if one or the other of the two components (e.g. water and cement; gypsum and cement; two-component synthetic plastic adhesive system) is already present in the prop casing 1, 2, before the other component is admitted into the same via the port 11, and that a device different from device D can be used.
  • the two components e.g. water and cement; gypsum and cement; two-component synthetic plastic adhesive system
  • apparatus for mechanically telescoping the sections 1, 2 apart to the requisite extent, once they have been placed in upright position, and this apparatus or another apparatus may be utilized to compress the spring 8 in preparation for insertion of the retainers 10.
  • apparatus may be provided for subjecting the prop casing 1, 2 to vibrations in order to compact and densify the flowable substance admitted into it, e.g. the concrete slurry, so as to obtain a denser product which, when hardened, is able to withstand greater stresses.
  • FIGS. 7A-7E are respective cross-sections through the prop casing section 2, taken in a plane which passes through the port 11, but with the bars 5, 7 omitted for simplicity.
  • FIG. 7A is a section through the prop casing after the same is erected at the location where a supporting column is to be produced.
  • the interior of the casing is empty, except for the (not illustrated) reinforcing bars 5, 7 and the possible presence of aggregate or of a component (also not shown) of the hardenable substance.
  • the injecting device D is now placed on the section 2, with its arms in the broken-line position which corresponds to the position of FIG. 5.
  • a spring clamp 30 (FIG. 6) having an opening 31 is placed around the section 2 so that its opening 31 registers with the port 11.
  • the arms 21 of the device D are then moved to the closed (solid-line) position shown in FIG. 7B, in which they are held by a retainer 32 (of e.g. steel, such as spring steel, or the like) which engages behind the hook-shaped ends of the arms 21.
  • the retainer could also be formed integrally with a free end of one of the arms 21, if desired, and its operation would still be the same.
  • the outlet opening 21a must register with the opening 31 which in turn registers with the port 11, as shown.
  • the operator then depresses the trigger 22 of the device D and the hardenable substances (or one of its components, if the other component is already present in the casing) is now injected through the port 11 until the casing 1, 2 is filled.
  • the section 2 is provided adjacent its inner end with a safety vent opening 12 which is normally located within, and then blocked by, the section 1.
  • a safety vent opening 12 which is normally located within, and then blocked by, the section 1.
  • the device D and the clamp 30 are swung about the section 2, until the outlet opening 20a and the opening 31 have moved out of registry with the port 11 which is now sealed by a solid (i.e. non-perforated) portion of the wall of clamp 30 (FIG. 7C).
  • the device D can then be removed, leaving behind the clamp 30 (FIG. 7D) which seals the port 11 and is not removed until the hardenable substance S has set, to form within the pit prop casing a solid supporting column or pillar E (FIG. 7E) which supports the overburden.
  • a separate one-way valve to prevent outflow from port 11 is not needed.
  • the caved-in area supports the overburden and thus reduces the pressure of the overlying strata on e.g. the face supports in a coal mine.
  • the pillars will, of course, be under pressure from the overburden at the time they are to be removed. Since they are thus firmly held between the roof and the floor they evidently cannot be simply taken away at will.
  • an arrangement may be provided such as the one which is shown in FIG. 8.
  • This arrangement utilizes an upright hollow cylindrical socket 40, the lower end of which is preferably provided with a base plate 42.
  • the socket 40 must be of a material which is strong enough to support the weight of the pillar P and also to withstand the expected pressures of the overburden, e.g. of steel; plate 42 may be welded to it.
  • the socket is provided with two oppositely located holes 41, 41 into which a wedge 43 (of e.g. steel) is inserted.
  • a supporting plate 44 preferably corresponding in its outline to the interior cross-section of the socket 40, rests on the wedge 43.
  • the socket 40 is put in position where a pillar P is to be produced.
  • One end of the pit prop casing (usually the lower end of the section 1) is then inserted into it from above, to rest on the plate 44. This is diagrammatically illustrated by a showing of the pillar P. Thereafter, the installation of the pit prop casing and the formation of the pillar P proceeds as described before.
  • the pillar P When, at a later time, the pillar P has served its purpose and is to be removed, impacts on the free end 43a of the wedge drive the wedge out of the holes 41, whereupon the plate 44 and the pillar P (usually still encased in the pit prop casing 1, 2) drop down onto the plate 42.
  • the upper end of the pillar thus becomes disengaged from the roof and the pillar can then be readily removed; if the roof is to be allowed to collapse, it will suffice simply to topple the pillar P, rather than to take it away. If circumstances permit, the socket 40 and its associated components can at that time be recovered for reuse.
  • FIG. 9 A similar arrangement, but operating on a hydraulic basis, is illustrated in FIG. 9 wherein like reference numerals designate the same elements as in FIG. 8.
  • FIG. 9 this same space in FIG. 9 contains a bladder 50 of e.g. elastomeric material (such as natural or synthetic rubber or synthetic plastic material).
  • the openings 41 are omitted, but the wall of socket 40 has a hole 51 in which a valve is installed which communicates with the interior of the bladder 50.
  • a liquid under pressure e.g. oil or water
  • the lower end of pit prop section 1 is inserted into the socket 40 to rest on the plate 44. Again, this is symbolically shown by illustration of the pillar P.
  • the bladder 50 Prior to the insertion or subsequent thereto but prior to admission of the hardenable substance into the pit prop casing, the bladder 50 is filled with hydraulic fluid (and might even be somewhat stretched), so that it is able to support the weight of the subsequently-to-be-constructed pillar P and also to withstand the pressure exerted by the overburden.
  • the material of bladder 50 must of course be able to withstand the stresses to which it will become exposed.
  • the valve 51 When, at a later point in time, the pillar P is to be removed, the valve 51 is opened to permit the escape of hydraulic fluid which is pressurized by the weight bearing upon the bladder via plate 44. This results in collapse of the bladder 50 so that plate 44 and pillar P can descend towards base plate 42, thus releasing the pillar P from the pressure of the overburden and permitting it to be removed or to be toppled. Again, the socket and associated components may be recovered for reuse, circumstances permitting.
  • FIGS. 8 and 9 are not limited to use with the inventive pit prop casing and cast-in-situ pillars or props, but could, instead, also be used with conventional prefabricated pit props of e.g. wood, metal or concrete.
  • pit props of any kind have the ability to yield to a limited extent to the very high settling pressures so that they will not become destroyed and can thereafter, when the pressure decreases as a new state of equilibrium is approached, reliably prevent further settling which would lead to roof breaks.
  • FIGS. 10-15 Several embodiments of an arrangement which protects the pit props (pillars or the like) against damage due to overload while allowing limited settling of the roof, are illustrated in FIGS. 10-15. These embodiments are advantageously used with a pit prop casing according to the invention (and with a pillar of hardenable material produced inside the casing); however, they can also be used with conventional prefabricated pit props of metal, steel or other materials.
  • FIG. 10 shows an overload protector having an upright tubular wall 60 of metal (usually steel) to the lower end of which plate 61 is secured by e.g. welding.
  • the base plate could also be of one piece with the tubular wall.
  • the inner diameter of the tubular wall 60 is greater in the upper zone a as compared to the lower zone b, so that a core 62 may be inserted within the confines of the wall in zone a.
  • the core 62 has the illustrated shape and may be provided in its lower side with a recess 65 to make it lighter in weight (hence easier to handle) and to save material. Due to the rounded configuration of the circumferential edge face 64 of the core, the latter rests on a shoulder 66 which forms the transition from the zone a to the zone b of wall 60.
  • this overload protector To use this overload protector, a worker places the overload protector upright on the floor and inserts the lower end of a diagrammatically shown prop casing 63 according to the invention (e.g. the one in FIG. 1) into the upper open end of the wall 60, so that it rests on the flat or substantially flat (e.g. ribbed) upper surface of the core 62.
  • the prop casing is then braced against the roof (not shown) and a pillar of hardened material formed in it, also in the manner described before.
  • a prefabricated pit prop of metal, wood or other suitable material could also be used and would be directly inserted into the wall 60 in lieu of the pit prop casing 63.
  • the resulting pressure (see the arrow) acting upon the pit prop i.e. either on the pillar of hardened material inside the inventive pit prop casing or upon a conventional pit prop used in its place
  • the pit prop will drive the pit prop downwardly, causing the core 62 to enter the zone b and, in so doing, to effect plastic deformation of the wall 60.
  • the strength of the material and the thickness of the wall 60 are so selected that this yielding (plastic deformation) will occur before the maximum load-carrying capacity of the pit prop 63 has been reached. This protects the pit prop from damage or destruction and allows a limited settling of the roof, with a view towards the reestablishment of an equilibrium condition at which the pit prop will no longer be subjected to pressures in excess of its capabilities.
  • the upright tubular wall has reference numeral 70 and the base plate is designated 71.
  • the two zones a and b obtain, as before.
  • a larger transition zone c connects the zones a and b since the core 72 is of downwardly frustoconical shape.
  • the core may again have a recess, here designated 74 and the pit prop (pit prop casing with pillar or conventional pit prop) is designated with reference numeral 73.
  • the operation of this embodiment is the same as in FIG. 10.
  • FIG. 12 Another embodiment which operates on the same principle as FIGS. 10 and 11 is shown in FIG. 12, where the tubular wall has reference numeral 80 and the base plate reference numeral 81.
  • the pit prop is designated with reference numeral 87.
  • the core in this embodiment has two axially spaced, downwardly frustoconical portions 83 and 84 which are connected by a reduced-diameter portion 85 of e.g. cylindrical shape.
  • the wall 80 again has different internal diameter zones, as shown, but in this embodiment two shoulders are formed, on each of which one of the portions 83, 84 rests.
  • the core may again be provided with a recess, here designated with reference numeral 86.
  • the two portions 83, 84 simultaneously effect outward plastic deformation of the wall 80 when the core is driven downwardly.
  • the portion 83 first causes a lesser deformation and, when the portion 84 reaches a wall portion which was already deformed by portion 83, it again causes a further deformation of the same wall portion.
  • the resistance offered by this arrangement to pressure acting upon the pit prop 87 can therefore be greater than that in FIGS. 10 and 11.
  • FIGS. 13-15 Three further embodiments of the inventive overload protector are described in FIGS. 13-15; these operate on a different principle than those of FIGS. 10-12.
  • tubular wall and the base plate have reference numerals 90 and 91, respectively, and the pit prop is designated with reference numeral 94.
  • a ring 92 (of e.g. steel) having an outer diameter somewhat greater than the inner diameter of the wall 90, is press-fitted into the same.
  • a supporting plate 93 for the pit prop 94 may be placed loosely on top of the ring 92 or may be suitably secured to it, as e.g. by welding.
  • the inner diameter of the wall 90 is here of constant cross-section but could instead have a slight convergence in downward direction.
  • the slightly rounded or bevelled bottom edge 95 of ring 92 facilitates its insertion into the wall.
  • the yieldable resistance to the downward movement of pit prop 94 under the influence of roof pressure is afforded by the high coefficient of friction between the inner circumferential surface of wall 90 and the outer circumferential surface of the pressfitted ring 92.
  • FIG. 14 shows an embodiment wherein the wall and the base plate are designated with reference numerals 100, 101 respectively.
  • the pit prop has reference numeral 105.
  • FIGS. 10-12 the core of FIGS. 10-12 is replaced with a ring 102 carrying a pit-prop supporting plate 104.
  • the ring 102 has its lower edge shaped as a cutting edge 103.
  • the upper part of the wall 100 has a somewhat larger diameter than the lower part, so that a shoulder exists at their juncture on which the cutting edge rests.
  • the resistance offered by the overload protector to downward movement of the pit prop 105 and the ring 102 under pressure on the former results from the fact that the cutting edge 103 cuts into the material of the wall 100 as this ring 102 moves downwardly.
  • FIG. 15 is a modification of the one in FIG. 14. Only a portion of the length of tubular wall 110 is shown; a base plate will be present as in the other embodiments. The pit prop has been omitted for simplicity.
  • the ring 111 carrying the pit-prop support plate, is of cylindrical shape, unlike the ring 102 of FIG. 14.
  • Ring 111 also has a lower cutting edge 112, produced by bevelling the inner surface of the ring as shown at 113.
  • the operation of this embodiment is the same as in FIG. 14.
  • the wall 110 has a larger upper and a smaller lower inner diameter, so that a step or shoulder is formed on which the cutting edge 112 rests until sufficient pressure on the pit prop causes the edge 112 to cut into the material of wall 110 as the ring 111 yields in downward direction.
  • the method and system according to the present invention make it possible to erect roof supports quickly, efficiently and at low cost in virtually any location where there is a need for such supports. Furthermore, the invention also enables a user to remove the installed supports even while they are under load (pressure) from the overburden and, in addition the invention provides enclosed protection for the installed supports to keep them from becoming damaged or destroyed.
  • the bladder in the embodiment of FIG. 8 may be reinforced; this can be done by embedding glass fibers or other fibers, or wires or other suitable material, in its wall.
  • the sockets intended to allow removal of the pit prop while the same is under load, or to protect the pit prop against overloading, need not be installed at the lower end of the pit prop or of the pit prop casing, but could also be installed at the upper end, between the same and the roof.
  • a different arrangement than the one shown in FIG. 4 may be used for injecting the hardenable substance into the prop casing. In FIG.
  • the cross-sectional configuration of the pit prop casing in FIG. 1 and of the various sockets in FIGS. 7-15 is shown to be circular but could, of course, be of any other desired shape, for example quadratic, octagonal (or, more generally, polygonal) or elliptical.
  • a further aspect of the invention suggests, as shown in FIG. 16, that prior to installation of the pit prop or pit prop casing 160 a support in form of a wire or steel mesh, plate or the like 161 be placed on the floor F to bridge the raised portions F' and depressed portions F" thereof. The pit prop is then produced inside the casing 160 as described before.
  • the lower end of the prop casing is provided with holes 162 through which some of the hardenable mass can flow out, to form a base or foot 163 about the lower end of the casing 160. Since the mass at this time is in flowable state, it will flow beneath the support 163 and fill the depressions F", creating a solid base whose presence prevents the floor F, or rather the raised portions F' thereof, against collapse due to being crushed when load acts from the roof on the pit prop.
  • the holes 162 could be omitted and the injecting device (e.g. the one in FIG. 4) be used to simply spray the hardenable mass around the lower end of casing 160 and beneath the support 161 to create the base 163.
  • a similar procedure may be employed at the top of the prop casing where the same engages the roof (not shown).
  • the support 163 (which serves, inter alia, to retain and facilitate bonding of the hardenable mass) extend from one to another of the pip prop casings (e.g. two casings installed at opposite sides of a gallery).
  • a reinforced connection e.g. a strip of cement reinforced by the embedded support 161
  • the injecting device can then be produced by using the injecting device to spray the hardenable material onto, around and beneath that portion of the support 161 which extends between the adjacent pit prop casings.
  • the same arrangement may also be used to connect the tops of adjacent casings, beneath the roof.

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  • On-Site Construction Work That Accompanies The Preparation And Application Of Concrete (AREA)
  • Joining Of Building Structures In Genera (AREA)
US05/957,355 1978-11-03 1978-11-03 Method of and apparatus for supporting an overburden Expired - Lifetime US4249837A (en)

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US05/957,355 US4249837A (en) 1978-11-03 1978-11-03 Method of and apparatus for supporting an overburden
AU46307/79A AU4630779A (en) 1978-11-03 1979-04-20 Mine roof support
DE19792941663 DE2941663A1 (de) 1978-11-03 1979-10-15 Verfahren und vorrichtung zum abstuetzen eines deckgebirges

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US05/850,096 Continuation-In-Part US4185940A (en) 1977-11-08 1977-11-08 Method and system for supporting a roof

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Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4314394A (en) * 1978-12-21 1982-02-09 Gte Products Corporation Photoflash lamp construction and method of making same
US4332512A (en) * 1979-05-22 1982-06-01 Bochumer Eisenhuette Heintzmann Gmbh & Co. Arrangement for erecting columnar supporting elements for underground excavations
US4605339A (en) * 1981-07-29 1986-08-12 Roger Bullivant Of Texas, Inc. Situ pile construction in ground liable to uplift
US5400994A (en) * 1991-01-22 1995-03-28 Dyckerhoff & Widmann Ag Of Munich Yieldable roof support system
US5538364A (en) * 1995-02-14 1996-07-23 Huntsman; Steven D. Yieldable mine post having a double ball and socket configuration
US5564867A (en) * 1993-11-13 1996-10-15 Bochumer Eisenhutte Heintzmann Gmbh & Co. Kg Resilienty compressible support column for use in a mine
US20050150185A1 (en) * 2002-02-15 2005-07-14 Hiroyasu Minayoshi Concrete pole
KR200446055Y1 (ko) 2009-01-09 2009-09-24 장인석 높이조절이 가능한 선박블록 지지대
US8851805B2 (en) 2012-08-30 2014-10-07 Burrell Mining Products, Inc. Telescopic mine roof support
WO2015164909A1 (en) * 2014-04-28 2015-11-05 Cougar Can Company Pty Ltd A telescopic pumpable prop assembly with improved ceiling impact properties
CN106522947A (zh) * 2016-11-22 2017-03-22 武汉理工大学 预应力人工矿柱
US9611738B2 (en) 2014-08-27 2017-04-04 Burrell Mining Products, Inc. Ventilated mine roof support
ES2633136A1 (es) * 2016-03-18 2017-09-19 Alejandro HUERGA FERNANDEZ Refuerzo de una torre tubular y procedimiento de realización
US9903203B2 (en) 2014-08-27 2018-02-27 Burrell Mining Products, Inc. Ventilated mine roof support
US9995140B2 (en) * 2013-11-22 2018-06-12 Fci Holdings Delaware, Inc. Yieldable prop with yieldable insert
CN113803090A (zh) * 2021-10-20 2021-12-17 石家庄铁道大学 隧道让压支护装置
WO2022065585A1 (ko) * 2020-09-25 2022-03-31 주식회사 미래이앤지 선박용 스툴 어셈블리
CN115596482A (zh) * 2022-10-26 2023-01-13 四川华蓥山龙滩煤电有限责任公司（Cn） 一种柔模混凝土沿空留巷液压支架
CN116122211A (zh) * 2023-04-14 2023-05-16 中铁三局集团有限公司 一种隧道壁快速除冰装置

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2920659C2 (de) * 1979-05-22 1981-10-01 Bochumer Eisenhütte Heintzmann GmbH & Co, 4630 Bochum Vorrichtung zum Errichten eines säulenartigen Stützelements für den untertägigen Bergbau
DE4115209A1 (de) * 1991-05-10 1992-11-12 Volker Merz Ausbaustuetze
DE4316390C1 (de) * 1993-05-17 1994-04-21 Volker Merz Ausbaustütze
CN111411994B (zh) * 2020-04-21 2024-06-18 中铁二院工程集团有限责任公司 穿越巨型溶洞的桥梁跨越分离式承载结构及其施工方法

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GB232990A (en) * 1924-04-26 1925-11-12 Paul Kaasmann Improvements in and relating to pit props
US1752101A (en) * 1926-12-22 1930-03-25 Meutsch Heinrich Mining prop
US1821020A (en) * 1929-06-17 1931-09-01 Mensforth Thomas Foot attachment for pit frops or steel arches employed as colliery or mining roof supports
FR712661A (fr) * 1930-08-14 1931-10-07 Pied souple et amovible pour étais en bois dans les mines
US2322855A (en) * 1942-02-09 1943-06-29 Halliburton Oil Well Cementing Method and apparatus for raising and permanently supporting heavy structures
DE740972C (de) * 1941-02-05 1943-11-01 Carl Tiefenthal Grubenstempel
US2451777A (en) * 1946-09-06 1948-10-19 Salas Miguel Combination jack and concrete form
GB653223A (en) * 1948-11-25 1951-05-09 Colcrete Ltd Improvements in or relating to the reinforcement in situ of tapered tubular poles with concrete or grout
DE920483C (de) * 1951-08-30 1955-03-17 Heinrich Nolting Nachgiebiger Stempel
US2753036A (en) * 1952-03-06 1956-07-03 Joy Mfg Co Mine roof support-equipped mining apparatus
GB770305A (en) * 1955-04-27 1957-03-20 Charles Patrick Maccarthy Improvements in and relating to underground roof supports
US2890854A (en) * 1956-01-09 1959-06-16 Gutehoffnungshuette Sterkrade Torsion pit prop
GB966592A (en) * 1961-11-18 1964-08-12 Hayden Nilos Ltd Improvements in or relating to mine shoring
GB1016292A (en) * 1963-05-15 1966-01-12 Stewarts & Lloyds Ltd A yielding strut
CH407518A (de) * 1963-08-22 1966-02-15 Staro Degasper & Co Längsverstellbare Strebe
US3292892A (en) * 1965-10-14 1966-12-20 Oscar J Abbott Adjustable form shore
DE1483943A1 (de) * 1966-06-30 1969-10-16 Hermann Schwarz Kg Nachgiebiges Stuetzelement fuer den Grubenausbau
US3594973A (en) * 1969-06-23 1971-07-27 Arlo Inc Method for developing a multiple-pole stand
US3690110A (en) * 1970-04-09 1972-09-12 George C Wiswell Jr Repairing or rehabilitating steel supported h-piles

Patent Citations (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB232990A (en) * 1924-04-26 1925-11-12 Paul Kaasmann Improvements in and relating to pit props
US1752101A (en) * 1926-12-22 1930-03-25 Meutsch Heinrich Mining prop
US1821020A (en) * 1929-06-17 1931-09-01 Mensforth Thomas Foot attachment for pit frops or steel arches employed as colliery or mining roof supports
FR712661A (fr) * 1930-08-14 1931-10-07 Pied souple et amovible pour étais en bois dans les mines
DE740972C (de) * 1941-02-05 1943-11-01 Carl Tiefenthal Grubenstempel
US2322855A (en) * 1942-02-09 1943-06-29 Halliburton Oil Well Cementing Method and apparatus for raising and permanently supporting heavy structures
US2451777A (en) * 1946-09-06 1948-10-19 Salas Miguel Combination jack and concrete form
GB653223A (en) * 1948-11-25 1951-05-09 Colcrete Ltd Improvements in or relating to the reinforcement in situ of tapered tubular poles with concrete or grout
DE920483C (de) * 1951-08-30 1955-03-17 Heinrich Nolting Nachgiebiger Stempel
US2753036A (en) * 1952-03-06 1956-07-03 Joy Mfg Co Mine roof support-equipped mining apparatus
GB770305A (en) * 1955-04-27 1957-03-20 Charles Patrick Maccarthy Improvements in and relating to underground roof supports
US2890854A (en) * 1956-01-09 1959-06-16 Gutehoffnungshuette Sterkrade Torsion pit prop
GB966592A (en) * 1961-11-18 1964-08-12 Hayden Nilos Ltd Improvements in or relating to mine shoring
GB1016292A (en) * 1963-05-15 1966-01-12 Stewarts & Lloyds Ltd A yielding strut
CH407518A (de) * 1963-08-22 1966-02-15 Staro Degasper & Co Längsverstellbare Strebe
US3292892A (en) * 1965-10-14 1966-12-20 Oscar J Abbott Adjustable form shore
DE1483943A1 (de) * 1966-06-30 1969-10-16 Hermann Schwarz Kg Nachgiebiges Stuetzelement fuer den Grubenausbau
US3594973A (en) * 1969-06-23 1971-07-27 Arlo Inc Method for developing a multiple-pole stand
US3690110A (en) * 1970-04-09 1972-09-12 George C Wiswell Jr Repairing or rehabilitating steel supported h-piles

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4314394A (en) * 1978-12-21 1982-02-09 Gte Products Corporation Photoflash lamp construction and method of making same
US4332512A (en) * 1979-05-22 1982-06-01 Bochumer Eisenhuette Heintzmann Gmbh & Co. Arrangement for erecting columnar supporting elements for underground excavations
US4605339A (en) * 1981-07-29 1986-08-12 Roger Bullivant Of Texas, Inc. Situ pile construction in ground liable to uplift
US5400994A (en) * 1991-01-22 1995-03-28 Dyckerhoff & Widmann Ag Of Munich Yieldable roof support system
US5564867A (en) * 1993-11-13 1996-10-15 Bochumer Eisenhutte Heintzmann Gmbh & Co. Kg Resilienty compressible support column for use in a mine
US5538364A (en) * 1995-02-14 1996-07-23 Huntsman; Steven D. Yieldable mine post having a double ball and socket configuration
US20050150185A1 (en) * 2002-02-15 2005-07-14 Hiroyasu Minayoshi Concrete pole
KR200446055Y1 (ko) 2009-01-09 2009-09-24 장인석 높이조절이 가능한 선박블록 지지대
US9347316B2 (en) 2012-08-30 2016-05-24 Burrell Mining Products, Inc. Telescopic mine roof support
US8851805B2 (en) 2012-08-30 2014-10-07 Burrell Mining Products, Inc. Telescopic mine roof support
US9995140B2 (en) * 2013-11-22 2018-06-12 Fci Holdings Delaware, Inc. Yieldable prop with yieldable insert
US10240458B2 (en) 2014-04-28 2019-03-26 Cougar Can Company Pty Ltd Telescopic pumpable prop assembly with improved ceiling impact properties
WO2015164909A1 (en) * 2014-04-28 2015-11-05 Cougar Can Company Pty Ltd A telescopic pumpable prop assembly with improved ceiling impact properties
US9611738B2 (en) 2014-08-27 2017-04-04 Burrell Mining Products, Inc. Ventilated mine roof support
US9903203B2 (en) 2014-08-27 2018-02-27 Burrell Mining Products, Inc. Ventilated mine roof support
ES2633136A1 (es) * 2016-03-18 2017-09-19 Alejandro HUERGA FERNANDEZ Refuerzo de una torre tubular y procedimiento de realización
CN106522947A (zh) * 2016-11-22 2017-03-22 武汉理工大学 预应力人工矿柱
WO2022065585A1 (ko) * 2020-09-25 2022-03-31 주식회사 미래이앤지 선박용 스툴 어셈블리
CN113803090A (zh) * 2021-10-20 2021-12-17 石家庄铁道大学 隧道让压支护装置
CN115596482A (zh) * 2022-10-26 2023-01-13 四川华蓥山龙滩煤电有限责任公司（Cn） 一种柔模混凝土沿空留巷液压支架
CN116122211A (zh) * 2023-04-14 2023-05-16 中铁三局集团有限公司 一种隧道壁快速除冰装置
CN116122211B (zh) * 2023-04-14 2023-07-04 中铁三局集团有限公司 一种隧道壁快速除冰装置

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AU4630779A (en) 1980-05-08
DE2941663A1 (de) 1980-05-14

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